Delivery and protection of health-promoting compounds such as polyphenols, including EGCG and related catechins, is an important challenge as polyphenols are not stable in water due to oxidation and are known to be bitter and/or astringent.
A solution to avoid the bitter taste of polyphenols is their encapsulation for preventing contact with the mouth. U.S. Pat. No. 6,190,591 discloses controlled release from discrete, solid particles which contain encapsulated and/or embedded components. JP2005-1245540 discloses a method for masking the astringency and bitterness of polyphenols by inclusion of casein. However, encapsulation is not suitable for any food product. Furthermore, water soluble compounds such as catechin are very difficult to encapsulate since they tend to leak out leading to short shelf life.
US 2010/0159105 discloses a food composition intended to reduce the bitterness of catechin characterized in that it contains at least 100 mg/1 of a catechins-Zn++ salt precipitate or a polymeric polyphenol compound—Zn++ salt precipitate and any mixture thereof.
Nanoparticles offer a suitable vehicle system for protection and delivery of pharmaceutical and nutraceutical agents. U.S. Pat. No. 6,290,974 teaches a composition comprising food additive comprising a preformed complex of β-lactoglobulin and a lipophilic nutrient selected from the group consisting of vitamin A, vitamin D, vitamin E, vitamin K1, cholesterol, and conjugated linoleic acid. In that disclosure the lipophilic nutrient is bound to β-lactoglobulin.
Core-shell nanoparticles of chitosan coated with native and denatured β-lactoglobulin for delivery of nutraceuticals are disclosed in Chen (Chen, et al. (2005) Biomaterials, Vol. 26, pages 6041-6053). Chen teaches that the native β-lactoglobulin has favorable properties compared to the denatured β-lactoglobulin.
WO 2009/130704 by one of the inventors of the present invention discloses a stable colloidal dispersion of nanoparticles comprising complexes of β-lactoglobulin and a polysaccharide, where preferably the stable colloidal dispersion of nanoparticles is transparent in an aqueous medium.
Nowhere in the art has it been taught or suggested to co-assemble nanoparticles of unfolded (denatured) β-lactoglobulin (β-Lg) and polyphenols.
The inventors of the present invention disclosed on Oct. 18, 2009 (3rd International Symposium, 18-21 Oct. 2009, Wageningen, The Netherlands) and in November-December 2010 (Shpigelman, et al. (2010) Food Hydrocolloids, Vol. 24, pages: 735-743) a co-assembled nanoparticle system based on thermally denatured β-lactoglobulin (β-Lg) and polyphenols. Such nanoparticle system has not been disclosed or suggested by the background art.